Phyllotreta nodicornis (Marsham, 1802)

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Widespread across southern and central Europe but generally very local and scarce, especially in northern regions, it occurs from Spain to Bulgaria and Romania in the south and extends north to the UK Germany and Poland; it also occurs in Morocco and Algeria and extends east through Asia Minor and Russia to Northern India. In the UK it is locally common across Southern and Central England north to the Humber but much more sporadic and scarce further north to southern Scotland and across Wales and the West Country. Typical habitats are wetland margins, heathland, calcareous grassland, wasteland, and damp woodland etc., usually in lowland situations (although it occurs up to 900 m in Turkey) and always with plenty of herbaceous vegetation. Adults occur year-round; they overwinter among litter or tussocks and are active from April until July or August, peaking in abundance during May and June. Host plants include various Resedaceae, mostly Wild Mignonette (Reseda lutea L.) and Weld (R. luteola L.) but also White Mignonette (R. alba L.), Corn Mignonette (R. phyteuma L.) and Common Mignonette (R. odorata L.) Watercress (Nasturtium officinale Aiton) has been recorded as a host in Mallorca, and more generally adults have been recorded feeding from a range of brassica plants including Wallflowers (Erysimum cheiri (L.), Radish (Raphanus raphanistrum L.), Turnip (Brassica rapa L.) and White Mustard (Sinapis alba L). The species is univoltine in the UK, adults may be swept from host foliage and their feeding is often a good sign of their presence, they produce small areas of holes which soon turn yellow or grey and die off. Little is known of the biology but larvae are known to develop within roots and pupation is thought to occur either in situ or in an earthen cell. Adults fly well and have been recorded in flight-interception and malaise traps during the spring and summer.

Phyllotreta nodicornis 1

Phyllotreta nodicornis 1

Phyllotreta nodicornis 2

Phyllotreta nodicornis 2

2.0-2.8 mm. Elongate and rather depressed, body entirely black with a metallic bronze or greenish reflection, these metallic colours often differing slightly between the forebody and the elytra, antennae dark with 1-3 paler basal segments, legs black with the tibial bases and tarsi paler. Frons impunctate across the centre, with only a few punctures near the posterior margins of the eyes, frontal furrows straight and strongly converging from the inner margin of the eyes to the antennal insertions. Antennae 11-segmented, dimorphic; in males the third antennomere is broadly triangular and the fourth is greatly expanded, in females the antennomeres 2 & 3 are short and the fourth is  narrow and slightly shorter than the fifth. Pronotum transverse, broadest about the middle and almost evenly curved to obtuse angles (from above), surface smoothly convex, without basal furrows or impressions, and finely and evenly punctured throughout. Elytra gently curved, sometimes almost parallel-sided, from rounded shoulders to separately-curved apical margins, surface without striae, randomly punctured throughout, a little more strongly so than the pronotum. Hind femora greatly enlarged, front and middle femora normal. Tibiae without external teeth, hind tibiae narrow with a small spur inserted about the middle of the simply-curved apex. Basal segment of front and middle tarsi broader in males.